[Feature Request]: Linking directly to the source code of the associated doc

[aniravi24]

For example, see the following hexdocs for the Phoenix web framework in Elixir.

https://hexdocs.pm/phoenix/Phoenix.html (The chainlink icon on the left (shows up on hover) links to the doc just like docgen, the tag icon on the right to the source code).

Not sure if docgen should present this in the exact same way, but having this functionality would be nice!